1. Field of the Invention
The present invention is concerned with a lineman's clamp stick equipped with torque-limiting means such that a workpiece can be tightened with the stick only to a desired torque level. More particularly, it is concerned with such a torque-limiting clamp stick wherein, in especially preferred forms, a removable, torque-limiting adapter is mounted onto the normal work end of an otherwise conventional clamp stick.
2. Description of the Prior Art
Elongated, insulative clamp sticks have long been used by linemen for their work in and around energized electrical lines or equipment. For example, certain types of clamp sticks are designed to mount and dismount electrical transmission and distribution equipment and, for this purpose, are provided with manually shiftable operating machanism for axially rotating the tool from a safe, remote position. In addition, such clamp sticks are normally provided with mechanism for axially shifting the hook into and out of the insulative body of the clamp stick for reasons of safety and ease of operations.
In many tightening operations where a clamp stick is conventionally employed, it would be desirable to have some limit to the amount of torque which can be applied to a workpiece. That is to say, it has been known for linemen to over-tighten connectors and thus deform or damage the equipment being mounted or an electrical line. On the other hand, the connectors must be tightened sufficiently to avoid high resistance connections which can lead to catstrophic failures. Of course, conventional torque wrenches cannot be used to measure applied torque in this context because this would subject the linemen to the extreme peril of electrical shock. Hence, the prior and unsatisfactory technique has been for the lineman to "guess" at the appropriate torque.
U.S. Pat. No. 2,514,063 discloses one type of clamp stick in widespread use today, and this patent is incorporated herein by reference.